The main cause of high concentration of dust particles in the air is traffic, particularly vehicles run on diesel. It is perhaps no surprise then that Stuttgart, as German's most congested city, comes top of the pile.

Dust particles can damage mucus membranes in the nasal passage and blood vessels in the lungs, which can increase the risk of lung cancer.

According to a study by the European Environmental Agency, dust particles cause 430,000 premature deaths in the EU per year.

Germany's worst 15 cities for dust particle pollution:

1. Stuttgart

2. Reutlingen, Baden-Württemberg (BW)

3. Gelsenkirchen, North Rhine-Westphalia (NRW)

4. Markgrönigen, BW

5. Aachen, NRW

6. Hagen, NRW

7. Munich

8. Duisburg, NRW

9. Heilbronn, BW

10. Ulm, BW

11. Dortmund, NRW

12. Herne, NRW

13. Cologne

14. Berlin

15. Oberhausen, NRW

The report also included figures on levels of nitrogen dioxide, usually a by-product of burning and especially present in fumes from vehicles with diesel engines.

Nitrogen dioxide can be harmful to asthma sufferers, and high concentrations can increase the risk of a heart attack.

German cities worst affected by NO2 pollution

1. Stuttgart

2. Munich

3. Reutlingen, BW

4. Düren, NRW

5. Kiel, Schleswig-Holstein (SH)

6. Limburg an der Lahn, Hessen (H)

7. Freiburg, BW

8. Heilbronn, BW

9. Ludwigsburg, BW

10. Schwäbisch Gmünd, BW

11. Berlin

12. Hamburg

13. Cologne

14. Düsseldorf

15. Leonberg, BW

One silver lining is that, unlike dust particle concentration and nitrogen dioxide levels, the amount of sulphur dioxide in the air hasn’t exceeded legal limits anywhere in Germany.

Sulphur dioxide is produced by burning coal and oil, and can cause acid rain. The SO2 levels have gone down in the last 20 years, and so the health of Germans isn’t at risk.

German cities with the highest levels are mostly in Saxony, a former GDR industrial heartland before reunification.